Document Detail


Potent osmoregulatory actions of homologous adrenomedullins administered peripherally and centrally in eels.
MedLine Citation:
PMID:  18922959     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The teleost adrenomedullin (AM) family consists of three groups, AM1/AM4, AM2/AM3, and AM5. In the present study, we examined the effects of homologous AM1, AM2, and AM5 on drinking and renal function after peripheral or central administration in conscious freshwater eels. AM2 and AM5, but not AM1, exhibited dose-dependent (0.01-1 nmol/kg) dipsogenic and antidiuretic effects after intra-arterial bolus injection. The antidiuretic effect was significantly correlated with the degree of associated hypotension. To avoid the potential indirect osmoregulatory effects of AM-induced hypotension, infusion of AMs was also performed at nondepressor doses. Drinking was enhanced dose-dependently at 0.1-3 pmol.kg(-1).min(-1) of AM2 and AM5, matching the potency and efficacy of angiotensin II (ANG II), the most potent dipsogenic hormone known thus far. AM2 and AM5 infusion also induced mild antidiuresis, while AM1 caused antinatriuresis. Additionally, AMs were injected into the third and fourth ventricles of conscious eels to assess their site of dipsogenic action. However, none of the AMs at 0.05-0.5 nmol induced drinking, while ANG II was highly dipsogenic. AM2 and ANG II injected into the third ventricle increased arterial pressure while AM5 decreased it in a dose-dependent manner, and both AM2 and AM5 decreased blood pressure when injected into the fourth ventricle. These data suggest that circulating AM2 and AM5 act on a target site in the brain that lacks the blood-brain barrier. Collectively, the present study showed that AM2 and AM5 are potent osmoregulatory hormones in the eel, and their actions imply involvement in seawater adaptation of this euryhaline species.
Authors:
Maho Ogoshi; Shigenori Nobata; Yoshio Takei
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-10-15
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  295     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2008 Dec 
Date Detail:
Created Date:  2008-12-10     Completed Date:  2009-01-22     Revised Date:  2010-09-24    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R2075-83     Citation Subset:  IM    
Affiliation:
Laboratory of Physiology, Ocean Research Institute, University of Tokyo, Tokyo, Japan. mogoshi@bio.titech.ac.jp
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological
Adrenomedullin / administration & dosage,  metabolism*
Angiotensin II / metabolism
Anguilla / physiology*
Animals
Atrial Natriuretic Factor / metabolism
Blood Pressure
Brain / metabolism*
Diuresis
Drinking
Fish Proteins / administration & dosage,  metabolism*
Heart Rate
Humans
Infusions, Parenteral
Injections, Intra-Arterial
Injections, Intraventricular
Peptide Hormones / administration & dosage
Time Factors
Urodynamics
Water-Electrolyte Balance*
Chemical
Reg. No./Substance:
0/ADM2 protein, human; 0/Fish Proteins; 0/Peptide Hormones; 11128-99-7/Angiotensin II; 148498-78-6/Adrenomedullin; 85637-73-6/Atrial Natriuretic Factor

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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